mortar additive hpmcMay 11th 2023
Ready-mixed mortar refers to wet-mixed mortar or dry-mixed mortar produced by a professional factory. It realizes industrial production, ensures the stability of quality from the source, and has many advantages such as good operability, less on-site pollution, and effective improvement of project progress. advantage. Ready-mixed (wet-mixed) mortar is transported from the production point to the site for use. Like commercial concrete, it has high requirements on its working performance. It is necessary to ensure a certain operating time. After adding water and mixing, it must have sufficient strength before initial setting. Good workability, can carry out normal construction and operation.
In order to make the performance of all aspects of the ready-mixed mortar meet the specifications and construction requirements, the mortar admixture is an essential component. Magnesium aluminum silicate thixotropic lubricant and hydroxypropyl methyl cellulose ether are commonly used water-retaining thickeners in mortar. Cellulose ether has good water-retaining properties, but it is expensive, and the amount of high air-entrainment causes serious air-entrainment in mortar. The strength is greatly reduced and other problems; the price of magnesium aluminum silicate thixotropic lubricant is low, but when it is mixed alone, the water retention is lower than that of cellulose ether, and the dry shrinkage value of the prepared mortar is large, and the cohesiveness is reduced. The effects of compounding of magnesium aluminum silicate thixotropic lubricant and cellulose ether on the consistency, layering degree, setting time, strength and other aspects of ready-mixed (wet-mixed) mortar are as follows:
1. Although the mortar prepared without adding water-retaining thickener has high compressive strength, its water-retaining property, cohesiveness and softness are poor, bleeding is more serious, and the operation feel is poor, so it is basically unusable. Therefore, water-retaining thickening material is an essential component of ready-mixed mortar.
2. When the magnesium aluminum silicate thixotropic lubricant and hydroxypropyl methyl cellulose ether are mixed alone, the construction performance of the mortar is obviously improved compared with the blank mortar, but there are also shortcomings. When single-doped with magnesium aluminum silicate thixotropic lubricant, the amount of magnesium aluminum silicate thixotropic lubricant has a great influence on the water consumption of one side, and the water retention is lower than that of cellulose ether; when single-doped with hydroxypropyl methylcellulose ether, The operability of the mortar is good, but when the content is high, the air-entrainment is serious, which leads to a great decrease in the strength of the mortar, and the price is relatively expensive, which increases the material cost to a certain extent.
3. In the case of ensuring the performance of the mortar in all aspects, the optimal dosage of magnesium aluminum silicate thixotropic lubricant is about 0.3%, and the optimal dosage of hydroxypropyl methylcellulose ether is 0.1%. The amount of blending is controlled in this ratio, and the comprehensive effect is better.
4. The ready-mixed mortar prepared by compounding magnesium aluminum silicate thixotropic lubricant and hydroxypropyl methyl cellulose ether has good workability, and its consistency and loss, delamination, compressive strength and other performance indicators can all meet the requirements Specifications and construction requirements.